The discharge of oil into water results in the formation of oil slicks, i.e. continuous films on said water of sub-millimeter thickness. Such oil slicks or films are undesirable not only from an aesthetic standpoint but also because cohesive oil slicks represent a serious hazard to marine life as well as a potential shore line contaminant.
Large area cohesive oil slicks are oftentimes the result of accidents in off-shore drilling operations of from tanker collisions. Various chemical techniques have been devised for responding to these accidents including the use of chemicals for dispersing the oil into the water such as is disclosed in U.S. Pat. No. 3,793,218 and as oil collection agents such as are disclosed in U.S. Pat. No. 3,959,134.
When these large area oil slicks are of viscous oil or oil whose viscosity was increased because of exposure to "weathering," only the presently known hydrocarbon solvent-based chemical dispersant formulations are generally useful as is well known in the art.
A hydrocarbon solvent-based chemical dispersant formulation is required which is more effective and efficient in promoting dispersion of heavy oil slicks than presently known formulations. Of additional importance for a versatile dispersant formulation for use on spills covering a wide area is that it must be capable of being applied efficiently by aerial spray from large aircraft with minimal drift off-target. Also, a more effective product is required for spills on fresh or low-salinity waters.
It is an object of the invention to provide a dispersant formulation which can both more effectively penetrate into and diffuse through heavy (highly viscous) oil slicks and be applied by means of an aerial spray.